1. Field of the Invention
The invention relates to a vehicle power control apparatus provided with a charging terminal for storing power from an alternating-current power supply outside of a vehicle to a secondary battery, and a discharging terminal for supplying power to an alternating-current load outside of the vehicle, as well as a control method of power for a vehicle.
2. Description of Related Art
In recent years, vehicles provided with a secondary battery (hereinafter referred to as an “onboard secondary battery”) that stores electric power (simply referred to as “power” in this specification) to be supplied to an electric motor used as a power source, such as hybrid vehicles that run using a combination of an engine and an electric motor, or electric vehicles that run using an electric motor, are continuing to gain popularity.
Some of these kinds of vehicles are provided with a vehicle power control apparatus that is able to charge the onboard secondary battery from an alternating-current (AC) power supply outside the vehicle, and supply power stored in the onboard secondary battery to an alternating-current load outside the vehicle (Japanese Patent Application Publication No. 2009-27811 (JP 2009-27811 A). The AC power supply is a commercial power supply, for example, and the AC load is a home appliance, for example.
JP 2009-27811 A describes a plug that can be connected to an AC power supply or an AC load outside the vehicle. This plug is a plug that can be used for both charging and discharging. With the vehicle power control apparatus described in JP 2009-27811 A, when an AC power supply outside the vehicle is connected to the plug, AC power from the AC power supply is input from the plug, converted to direct-current (DC) power by a predetermined inverter, and charged to the onboard secondary battery. Also, when an AC load outside the vehicle is connected to the plug, power stored in the onboard secondary battery is converted into AC power by a predetermined inverter, and then supplied to the AC load from the plug.
In JP 2009-27811 A, as described above, a charging terminal that inputs power from an AC power supply outside the vehicle, and a discharging terminal that supplies power to an AC load outside the vehicle are formed with a single plug. The charging terminal and the discharging terminal can also be formed separately. For example, an idea to use an outlet of the same shape as an AC 100 V outlet as the discharging terminal, and use a plug that can be connected to the AC 100 V outlet as the charging terminal has been proposed (hereinafter, this proposal will be referred to as the “proposed example”).
In the proposed example described above, if a user mistakenly connects the charging terminal to the discharging terminal, a cycle will be created in which power discharged from the onboard secondary battery is charged to the onboard secondary battery via the discharging terminal and the charging terminal. Power stored in the onboard secondary battery will be consumed due to power loss that occurs with this cycle. Therefore, there is a need to be able to detect this kind of improper connection, and be able to notify the user of the vehicle.